Detection of saliva proteins modulated secondary to ductal carcinoma in situ of the breast

ABSTRACT

A method of differentiating among the presence of ductal carcinoma in situ in the breast, benign fibroadenoma of the breast, and non-cancerous breast tissue in a subject is disclosed. The method comprises: measuring the concentration of at least one protein biomarker selected from a group of forty-nine differentially expressed proteins in the saliva of persons with DCIS, or benign fibroadenoma, or in persons who are cancer-free. The resulting test data is compared to a reference panel. From the comparison the presence in the subject of either ductal carcinoma in situ of the breast, or benign fibroadenoma of the breast is determined.

BACKGROUND

1. Technical Field

The invention generally relates to methods and compositions fordiagnosing breast cancer, and, more particularly, to such methods andcompositions which use the differential expression of protein biomarkersin the saliva of an individual to differentiate among ductal carcinomain situ of the breast, benign fibroadenoma and non-cancerous tissue inthat individual.

2. Description of Related Art

Conventional physical examination and mammography are useful screeningprocedures for the early detection of breast cancer. However, they canproduce a substantial percentage of false positive and false negativeresults especially in women with dense parenchymal breast tissue.Consequently, screening results in a number of negative biopsy resultsyielding a high percentage of false positives. There is also ademonstrated lack of sensitivity in detecting cancerous lesions inyounger women yielding a significant percentage of false negatives.Although advanced technology in the field of mammography allows morereliable detection of small lesions of the breast, a clear need existsfor added modalities of screening, particularly for diagnosing cancer inyounger women.

There has been extensive use of immunohistochemistry to detectexpression of specific biomarkers as a potential adjunct diagnosticprocedure for certain tumors. Primarily, the markers have been found inserum and in tissues. Protein tumor markers such as c-erbB-2 (erb) andCathespin-D (CD) have been assayed in tissue and shown to correlate withaggressive lesions.

The term “proteomics” was originally defined to represent the analysisof the entire protein component of a cell or tissue, but that term nowencompasses the study of expressed proteins, including identificationand elucidation of the structure-function relationship under healthyconditions and disease conditions. In combination with genomics,proteomics can provide a holistic understanding of the biologyunderlying disease processes. Information at the level of the proteomeis critical for understanding the function of specific cell types andtheir role in health and disease (1, 2).

Protein expression and function are subject to modulation throughtranscription as well as through posttranscriptional and translationalevents. Multiple RNA species can result from one gene through a processof differential splicing. Additionally, there are more than 200post-translation modifications that proteins could undergo that affectfunction, protein-protein and nuclide-protein interaction, stability,targeting half-life, and so on (6), all contributing to a potentiallylarge number of protein products from one gene. Identifying andunderstanding these changes are the underlying themes in proteomics(6-9).

Technological advancements have benefited proteomic research to thepoint where saliva is now being assayed for protein content using thelatest available proteomic technology (10). There is a paucity ofinformation regarding the salivary proteome and its constituents in thepresence of disease such as carcinoma. One inventor's previous studiesusing immunological techniques have demonstrated that saliva from breastcancer patients exhibited elevated levels of c-erbB-2, CA 15-3, EGFR,cathepsin D and p53, suggesting that there is communication between thebreast tumor and the salivary gland (11, 12). In single analyte reports,additional low-abundance proteins such as HER2/neu, Waf-1, pantropicp53, EGFR and cathepsin D were found to be altered (12). Recently, thetumor biomarkers CA 125, c-erB-2 (erb) and Cathespin-D (CD) have beendetected in saliva and employed in a diagnostic panel for the initialdetection and follow-up screening of breast cancer patients. There iscontinuing interest in the development of adjunct diagnostic proceduresto enhance breast cancer screening.

BRIEF SUMMARY

In accordance with certain embodiments of the invention, a method ofdiagnosing the likelihood of the presence or occurrence of breast tumorin a test subject is provided. The method comprises (a) measuring in asaliva sample from the test subject the concentration of at least afirst protein biomarker, wherein each biomarker is known to bedifferentially expressed in breast tumor and tumor-free breast tissue,wherein the breast tumor comprises benign fibroadenoma or ductalcarcinoma in situ of the breast (DCIS), to provide a set of test datacomprising a concentration value of each said protein biomarker in thesaliva sample. The term “concentration value” may be a quantitativeamount or any other appropriate indication of a concentration, such as,for example, a colorimetric indicator score (e.g., +/−). The methodfurther includes (b) comparing the test values to a reference panelcomprising (1) a mean concentration value of each said protein in salivafrom a group of breast tumor-free individuals (reference control group),(2) a mean concentration value of each said protein in saliva from agroup of individuals with DCIS (reference DCIS group), or from a groupof individuals with benign fibroadenoma of the breast (reference benigngroup), or from both the DCIS group and the benign group; and (c)determining from that comparison a diagnosis of likelihood of thepresence or occurrence of a breast tumor in the test subject. In someembodiments the mean concentration ranges include a tolerance range orstatistical error range.

In some embodiments, in (a), at least the first biomarker is known to bedifferentially expressed among benign fibroadenoma, DCIS and tumor-freebreast tissue; in (b), step (2) comprises: (2′) a mean concentrationvalue of each said protein in saliva from the reference DCIS group, and(2″) a mean concentration value of each said protein in saliva from thebenign group in the reference panel, and in (c), the previouslydescribed step of “determining” comprises determining from thecomparison a diagnosis of likelihood of the presence or occurrence ofeither DCIS or fibroadenoma of the breast in the test subject.

In some embodiments, the concentration value of at least the firstprotein biomarker in the reference panel is significantly different inthe saliva of the DCIS group in the reference panel and/or in the salivaof the benign group in the reference panel, relative to the respectivelevel of each said protein biomarker in the saliva of the control groupin the reference panel. In certain embodiments, the concentration valuedifference of at least the first protein biomarker is significant at alevel in the range of p<0.05 to p<0.0001. In some embodiments, theconcentration value difference of the first protein biomarker issignificant at a level in the range of p<0.001 to p<0001.

In some embodiments, at least the first protein biomarker is selectedfrom the group consisting of CAH6, K2C4, CYTA, FABP4, IGHGI, TRFL,BPIL1, CYTC, HPT, PROF1 and ZA2G, and, in (c), the above mentioned stepof “determining” comprises determining from the comparison a diagnosisof likelihood of the presence or occurrence of DCIS in the test subject.

In some embodiments, at least the first protein biomarker is selectedfrom the group consisting of ENOA, IGHA2, IL-1ra, S10A7, SPLC2, and, in(c), the “determining” step comprises determining from the comparison adiagnosis of likelihood of the presence or occurrence of fibroadenoma inthe test subject.

In some embodiments, the reference panel is prepared by analyzingsalivary proteins by isotopic labeling and liquid chromatography tandemmass spectrometry to characterize salivary proteins from each saidgroup, and determining from the above-mentioned analysis thedifferential concentrations of the protein biomarkers in individualswith ductal carcinoma in situ of the breast, in individuals with benignfibroadenoma of the breast, and in individuals free of both ductalcarcinoma in situ and benign fibroadenoma.

In some embodiments, in step (a), “measuring” comprises analyzing thesalivary protein-containing sample by isotopic labeling and liquidchromatography tandem mass spectrometry to characterize the proteinbiomarkers. In some embodiments, the isotopic labeling comprisesdifferential isotopic labeling of salivary proteins of at least firstand second saliva samples.

In some embodiments, in step (b), the “comparing” step yields acomparison result in which the concentration value of at least a firstprotein biomarker is a greater than 50% change relative to the meanconcentration value of the respective protein in the control group ofthe reference panel.

In some embodiments, a first saliva sample is obtained from the testsubject, and, in (a), the set of test data is a first set of test data.In this case, the method further comprises: (d) obtaining a secondsaliva sample from the test subject subsequent to the first salivasample; (e) measuring the concentration of at least the first proteinbiomarker in the second saliva sample, to provide a second set of testdata comprising a second concentration value of each protein biomarkerin the saliva sample; (f) comparing the second set of test data to thereference panel; and (g) determining from the result of that comparisona diagnosis of likelihood of the presence or occurrence of either DCISor benign fibroadenoma of the breast in the test subject.

In some embodiments, the method further includes (h) comparing thesecond set of test data to the first set of test data to determinewhether a difference in the concentration value of at least the firstprotein biomarker exists between the first and second sets of test datafor the test subject. In some embodiments, the first saliva sample isobtained prior to surgical removal of cancerous breast tissue from thesubject. In certain embodiments, the test subject has receivedtherapeutic treatment for breast cancer (e.g., chemotherapy) prior toobtaining the second saliva sample, and in some cases, determining acomparative decrease in at least the first protein biomarkerconcentration in the second sample relative to the first sampleindicates that the treatment regimen is effective.

The potential diagnostic benefits arising from embodiments of theinvention include the overall management of breast cancer in women. Thediagnosis of breast cancer at an earlier stage allows a woman morechoice in selection of various treatment options. A saliva based testwould be potentially useful in the postoperative management of cancerpatients. In some embodiments of the above described methods, followingtumor removal, a decrease in marker concentration will follow andeventually plateau to within a normal level indicating that the patientis free of disease. In contrast, a persistently high level of salivarymarkers will be indicative of tumor recurrence or persistence. In someembodiments, saliva is potentially a cost effective method formonitoring the effectiveness of chemotherapy, in which decreases inmarker concentrations are observed if the treatment regimen iseffective. These and other embodiments, features and potentialadvantages will become apparent with reference to the followingdescription and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a set of Venn diagrams showing overlapping proteins betweenthree groups of women, in accordance with an exemplary set of dataillustrating an embodiment of the invention.

FIG. 2 is a chart showing the percentages of the 130 proteins from FIG.1 that correspond to respective functions.

FIG. 3 is a chart showing the differential protein expression in cancersaliva (darker bars) or benign saliva (lighter bars) versus normalcontrol represented by the 0 position.

FIG. 4 is a chart showing the differential protein expression in cancersaliva (bars) versus benign saliva represented by the 0 position.

DEFINITIONS

In the following discussion and in the claims, the terms “comprising,”“including” and “containing” are used in an open-ended fashion, and thusshould be interpreted to mean “including, but not limited to . . . ”.

The singular forms “a,” “an,” and “the” include plural referents unlessthe context clearly dictates otherwise.

The term “about,” when used in the context of a numerical value, meansapproximately or reasonably close to the given number, and generallyincludes, but is not limited to, ±10% of the stated number.

The term “secondary to carcinoma of the breast,” when referring to oneor more up-regulated or down-regulated proteins, means resulting frommetabolic or regulatory effects on the other tissues, fluids orstructures due to carcinoma of the breast.

The term “salivary proteome” refers to the complement of proteins andpeptides expressed in the saliva of a subject at a particular time andunder given conditions.

The term “concentration value” refers to a quantitative amount or anyother appropriate indication of a concentration, such as, for example, acolorimetric indicator score (e.g., +/−).

DETAILED DESCRIPTION

It was investigated in the present studies whether protein-by-productssecondary to cancer related oncogenes that are over or under expressedappear in the saliva of breast cancer patients. It is proposed thatsaliva is a fluid suffused with solubilized protein by-products ofoncogenic expression and these proteins are modulated secondary toductal carcinoma in situ (DCIS) of the breast. Additionally, there aresalivary protein profiles that are unique to both DCIS and fibroadenomatumors. Such differences between DCIS and fibroadenoma are potentiallyvaluable for noninvasively detecting and diagnosing breast cancer.

Saliva was selected for investigation as a diagnostic fluid primarilyfor two reasons: 1) collection of saliva is a non-invasive procedurethat can be conducted in any environment requiring no special skills orequipment; and 2) the physiology of the oral cavity is such that theflow of secreted fluid is continually flushing and refreshing the fluidcontent of the mouth. Therefore, the composition of the fluid at anymoment temporally reflects the metabolic activity of the secretoryelements generating that fluid. There are also significant potentialadvantages over the study of plasma. In plasma the concentration ofproteins can vary over nine orders of magnitude, which severelydiminishes the likelihood of detecting those proteins at the lower endof the scale. The second consideration is that blood is composed ofpeptides, proteins and cells that have half lives ranging from secondsto weeks or even a month or more. As a consequence, the presence of agiven substance might not accurately reflect the current state of theorganism.

Protein profiling was performed on three pooled, stimulated whole salivaspecimens. One specimen consisted of pooled saliva from 10 healthysubjects, another specimen was a pooled saliva specimen from 10 benigntumor patients (fibroadenomas), and the third specimen was from 10subjects diagnosed with ductal carcinoma in situ (DCIS). Fibroadenomawas selected due to its high prevalence among benign breast tumors. DCISwas selected as this represents the lowest detectable tumor loadaccording to the AJCC Cancer Staging Handbook, Part VII Breast (13). Thecancer cohort, internally, was estrogen, progesterone and Her2/neureceptor status negative as determined by the pathology report. Allsubjects were matched for age and race and were non-tobacco users.

Saliva Collection and Sample Preparation. Stimulated whole salivarygland secretion is based on the reflex response occurring during themastication of a bolus of food. Usually, a standardized bolus (1 gram)of paraffin or a gum base (generously provided by the Wrigley Co.,Peoria, Ill.) is given to the subject to chew at a regular rate. Theindividual, upon sufficient accumulation of saliva in the oral cavity,expectorates periodically into a preweighed disposable plastic cup. Thisprocedure is continued for a period of five minutes. The volume and flowrate is then recorded along with a brief description of the specimen'sphysical appearance, similar to the procedure described by Berkhed andHeintze (14). The cup with the saliva specimen is reweighed and the flowrate determined gravimetrically. This salivary collection method may bemodified for more consistent protein analyses as described by Streckfuset al. (15). A protease inhibitor from Sigma Co (St. Louis, Mich., USA)is added along with enough orthovanadate from a 100 mM stock solution tobring its concentration to 1 mM. The treated samples are centrifuged for10 minutes at approximately 15,000×g in a conventional table topcentrifuge. The supernatant is divided into 1 ml aliquots and frozen at−80° C.

LC-MS/MS Mass Spectroscopy with Isotopic Labeling. Mass spectrometry,liquid chromatography, analytical software and bioinformatics techniquesare used to analyze complex salivary peptide mixtures, wherein suchtechniques are capable of detecting differences in abundance of a givenprotein of over 8 orders of magnitude, as described by Wilmarth et al.(16). For example, isotopic labeling coupled with liquid chromatographytandem mass spectrometry (IL-LC-MS/MS) to characterize the salivaryproteome is employed as described by Gu et al. (17). The preferredmethod is a mass spectroscopy based method that uses isotope coding ofcomplex protein mixtures such as tissue extracts, blood, urine or salivato identify differentially expressed proteins, according to the methodof Shevchenko, et al. (18). In this way, changes in the level ofexpression of a protein are readily identified, thus permitting theanalysis of putative regulatory pathways and providing informationregarding the pathological disturbances in addition to potentialbiomarkers of disease. In embodiments, the analysis is performed on atandem QqTOF QStar XL mass spectrometer (Applied Biosystems, FosterCity, Calif., USA) equipped with an LC Packings (Sunnyvale, Calif., USA)HPLC for capillary chromatography. The HPLC is coupled to the massspectrometer by a nanospray ESI head (Protana, Odense, Denmark) formaximal sensitivity, as described by Shevchenko, et al. (18). Anadvantage of tandem mass spectrometry combined with LC is enhancedsensitivity and the peptide separations afforded by chromatography.Thus, even in complex protein mixtures, MS/MS data can be used tosequence and identify peptides by sequence analysis with a high degreeof confidence.

Isotopic labeling of protein mixtures has proven to be a usefultechnique for the analysis of relative expression levels of proteins incomplex protein mixtures such as plasma, saliva urine or cell extracts.There are numerous methods that are based on isotopically labeledprotein modifying reagents to label or tag proteins to determinerelative or absolute concentrations in complex mixtures. The higherresolution offered by the tandem Qq-TOF mass spectrometer is ideallysuited to isotopically labeled applications. The recently introducediTRAQ reagents (Applied Biosystems) are amino reactive compounds thatare used to label peptides in a total protein digest of a fluid (17, 19,20). The tag remains intact through TOF-MS analysis; however, it isrevealed during collision induced dissociation by MSMS analysis. Thus,in the MSMS spectrum for each peptide there is a fingerprint indicatingthe amount of that peptide from each of the different protein pools.Since virtually all of the peptides in a mixture are labeled by thereaction, numerous proteins in complex mixtures are identified and canbe compared for their relative concentrations in each mixture. Thus evenin complex mixtures there is a high degree of confidence in theidentification.

Salivary Protein Analyses With iTRAQ. The saliva samples are thawed andimmediately centrifuged to remove insoluble materials. The supernatantis assayed for protein using the Bio-Rad protein assay (Hercules,Calif., USA) and an aliquot containing 100 μg of each specimen isprecipitated with 6 volumes of −20° C. acetone. The precipitate isresuspended and treated according to the iTRAQ™ manufacturer'sinstructions. Protein digestion and reaction with iTRAQ labels arecarried out according to the manufacturer's instructions (AppliedBiosystems, Foster City, Calif.). Briefly, the acetone precipitableprotein is centrifuged in a table top centrifuge at 15,000×g for 20minutes. The acetone supernatant is removed and the pellet resuspendedin 20 μl dissolution buffer. The soluble fraction is denatured anddisulfides reduced by incubation in the presence of 0.1% SDS and 5 mMTCEP (tris-(2-carboxyethyl)phosphine)) at 60° C. for one hour. Cysteineresidues are blocked by incubation at room temperature for 10 minuteswith MMTS (methyl methane-thiosulfonate). Trypsin is added to themixture to a protein:trypsin ratio of 10:1. The mixture is incubatedovernight at 37° C. The protein digests are labeled by mixing with theappropriate iTRAQ reagent and incubating at room temperature for onehour. On completion of the labeling reaction, the four separate iTRAQreaction mixtures are combined. Since there are a number of componentsthat might interfere with the LCMSMS analysis, preferably the labeledpeptides are partially purified by a combination of strong cationexchange followed by reverse phase chromatography on preparativecolumns, employing techniques that are known in the art. The combinedpeptide mixture is diluted 10 fold with loading buffer (10 mM KH₂PO₄ in25% acetonitrile at pH 3.0) and applied by syringe to an ICATCartridge-Cation Exchange column (Applied Biosystems, Foster City,Calif.) column that has been equilibrated with the same buffer. Thecolumn is washed with 1 ml loading buffer to remove contaminants. Toimprove the resolution of peptides during LCMSMS analysis, the peptidemixture is partially purified by elution from the cation exchange columnin 3 fractions. Stepwise elution from the column is achieved withsequential 0.5 ml aliquots of 10 mM KH₂PO₄ at pH 3.0 in 25% acetonitrilecontaining 116 mM, 233 mM and 350 mM KCl respectively. The fractions areevaporated by Speed Vac to about 30% of their volume to remove theacetonitrile and then slowly applied to an Opti-Lynx Trap C18 100 μlreverse phase column (Alltech, Deerfield, Ill.) with a syringe. Thecolumn is washed with 1 ml of 2% acetonitrile in 0.1% formic acid andeluted in one fraction with 0.3 ml of 30% acetonitrile in 0.1% formicacid. The fractions are dried by lyophilization and resuspended in 10 μl0.1% formic acid in 20% acetonitrile. Each of the three fractions isanalyzed by reverse phase LCMSMS.

Reverse Phase LC-MS/MS. The desalted and concentrated peptide mixturesare quantified and identified by nanoLC-MS/MS on an API QSTAR XL massspectrometer (ABS Sciex Instruments) operating in positive ion mode. Thechromatographic system consists of an UltiMate nano-HPLC and FAMOSautosampler (Dionex LC Packings). Peptides are loaded on a 75 μm×10 cm,3 μm fused silica C18 capillary column, followed by mobile phaseelution: buffer (A) 0.1% formic acid in 2% acetonitrile/98% Milli-Qwater and buffer (B): 0.1% formic acid in 98% acetonitrile/2% Milli-Qwater. The peptides are eluted from 2% buffer B to 30% buffer B over 180minutes at a flow rate 220 nL/min. The LC eluent is directed to a NanoESsource for ESI/MS/MS analysis. Using information-dependent acquisition,peptides are selected for collision induced dissociation (CID) byalternating between an MS (1 sec) survey scan and MS/MS (3 sec) scans.The mass spectrometer automatically chooses the top two ions forfragmentation with a 60 s dynamic exclusion time. The IDA collisionenergy parameters were optimized based upon the charge state and massvalue of the precursor ions. For each saliva sample set there are threeseparate LCMSMS analyses.

The accumulated MSMS spectra are analyzed by ProQuant and ProGroupsoftware packages (Applied Biosystems) using the SwissProt fastadatabase for protein identification. The ProQuant analysis is carriedout with a 75% confidence cutoff with a mass deviation of 0.15 Da forthe precursor and 0.1 Da for the fragment ions. The ProGroup reports aregenerated with a 95% confidence level for protein identification.

Bioinformatics. The Swiss-Prot database is employed for proteinidentification while the PathwayStudio® bioinformatics software packageis used to determine regulatory pathways and distribution of proteinsaccording to function. Venn diagrams may be constructed, using, forexample, the Venn Diagram Plotter software program presently availablefrom the U.S. National Center for Research Resource (43). Graphiccomparisons with log conversions and error bars for protein expressionare produced using the ProQuant® software, for example.

Table 1 summarizes the results of an exemplary iTRAQ analysis of salivasamples carried out as described above. Overall protein comparisonsbetween benign vs. healthy, cancer vs. benign and cancer vs. healthyadult female subjects are shown. In total, 130 proteins were identifiedat a confidence level >95, and of those, 72 proteins were identifiedat >99 confidence level. Of these 130 proteins, there were 40 proteinsthat were determined to be expressed significantly differently (p<0.05)in the benign or tumor saliva compared to healthy controls. FIG. 1 is aVenn diagram of these proteins showing the overlapping proteins amongthe three groups of women.

Table 2 contains a list of the up-regulated (n=14) and down-regulated(n=9) proteins for the pooled saliva sample composed of individualsdiagnosed with a fibroadenoma (benign tumor). The fold increase ofprotein and p-values are also presented. As shown in Table 2, of the 29proteins, 9 (69%) were significant at the p<0.001 to p<0.0001 levels and7 of those 9 proteins had a greater than 50% change in concentration.

Table 3 contains a list of the up-regulated (n=20) and down-regulated(n=12) proteins observed in the Stage 0 cancer saliva compared tocontrols. “Stage 0 cancer” refers to breast tumor in which the stage ismicroscopic and demonstrates in situ involvement. The Stage 0 cancersaliva samples were obtained from women diagnosed with ductal carcinomain situ. There were 15 proteins that showed a 1.5 fold increase inlevels in the cancer compared to control subjects. Of these 15differentially expressed proteins, 12 were significant at the p<0.001 top<0.0001 levels. Each of the proteins listed in Table 3 is referenced inthe literature as having been found in blood from cancer subjects and/orin cell supernatants from cancer cell lines. Of the 32 proteins thatwere up- or down-regulated secondary to carcinoma of the breast, 79% ofthose differentially expressed proteins are cited in the literature asbeing involved, molecularly, with breast cancer (27-36). The functionsattributed to these proteins are shown in FIG. 2, along with anindication of the percentage of the total number of proteins thatcorrespond to those respective functions.

A comparison of the differentially expressed proteins is shown ingraphical form in FIG. 3. In this figure the log of the ratios forbenign vs control and cancer vs control is plotted for each of theproteins. The error bars are the log of the error factor calculated bythe ProQuant™ software. This comparison illustrates that there are anumber of significant differences in the expression levels of severalproteins between the cancer and benign saliva samples. A directcomparison of protein expression ratios between the benign and cancerpooled specimens that exhibited overlap or commonality among theproteins is shown in Table 4. Among the comparison of the overlappingproteins, the levels of 10 proteins fell at or below a p-value of 0.001and the levels of 9 proteins represented a greater than 50% differencein the cancer saliva samples compared to benign saliva samples. Thesedata are replotted in log form in FIG. 4.

In brief, three pooled (n=10 subjects/pool) stimulated whole salivaspecimens from women were analyzed. One pooled specimen was from healthywomen, another pooled specimen from women diagnosed with a benign breasttumor and the other one pooled specimen was from women diagnosed withductal carcinoma in situ (DCIS). Differential expression of proteins wasmeasured by isotopically tagging proteins in the tumor groups andcomparing them to the healthy control group. Experimentally, saliva fromeach of the pooled samples was trypsinized and the peptide digestslabeled with the appropriate iTRAQ reagent. Labeled peptides from eachof the digests were combined and analyzed by reverse phase (C18)capillary chromatography on an Applied Biosystems QStar LC-MS/MS massspectrometer equipped with an LC-Packings HPLC.

With respect to the overall analyses, the total number of salivaryproteins reported in healthy individuals at the 95% confidence levelswas 130 in the exemplary study disclosed herein. By comparison, in priorstudies that used 2D gel and mass spectrometry, about 100-102cancer-related salivary proteins were reported (16, 24). In still otherprior studies, about 300 cancer-related salivary proteins were reportedbased on both 2D gel and “shotgun” proteomic techniques (21).Differences in the number of total proteins identified are probably aresult of different technologies, profiling based on single samples orin collection and/or using single individual profiling (non-pooledspecimen) or in collection and/or sampling techniques (37).

Of the 130 proteins presently identified in the saliva specimens, fortynine proteins were differentially expressed between the healthy controlpool and the benign and cancer patient groups. Table 3 lists theproteins for the healthy pool vs. benign tumor pool, and Table 4 liststhe proteins for the healthy pool vs. cancer tumor pool. As illustratedin Table 4, many of these proteins have been reported as being eitherup- or down-regulated in blood and cancer tissue. There is also anoverlap of 13 up-regulated proteins and five down-regulated proteinsbetween the protein profiles, leaving the benign group with fiveproteins that are unique to fibroadenomas (ENOA, IGHA2, IL-1 ra, S10A7,SPLC2) and 11 proteins unique to DCIS (CAH6, K2C4, CYTA, FABP4, IGHGI,TRFL, BPIL1, CYTC, HPT, PROF1, ZA2G). FIG. 1 shows Venn diagrams of theoverlapping proteins between the three groups of women. Notably,two-thirds of the total “overlap” proteins were up-regulated. Withoutwishing to be limited to any specific theory to explain this phenomenon,it is proposed that a portion of the up-regulated proteins thatexhibited overlap are associated with pathways which are common to bothdisorders. This would include the proteins associated with cytoskeletonand cell growth. The benign tumor was targeted in order to increase thespecificity of the panel of markers. If there are markers specific to abenign tumor and other markers specific only to the malignancy, then theprobability of making the correct clinical assessment is furtherincreased.

Tables 5, 6 and 7 represent a comparison of the healthy control andcancer proteins which overlapped each group. As illustrated in Tables5-7, changes are listed in order of confidence, level 3 being thehighest confidence. Confidence levels are defined as follows: Level 3:Changes greater than 2 fold from good quality signals that also pass avisual inspection. Level 2: Changes greater than 2 fold from goodquality signals that do not pass visual inspection. Level 1: Changesgreater than 2 fold from low quality signals. Level 0: No significantprotein changes.

In this comparison, only seven proteins remained significantly differentin the presence of carcinoma (≦p<0.005). This would include the proteinsassociated with exocytosis, the cytoskeleton and immuno-response. As thecell proliferation process is further enhanced in the presence ofcarcinoma, these proteins are expected to be significantly up-regulatedin the case of carcinoma. FIGS. 3 and 4 provide further illustration ofthe protein comparisons.

Without wishing to be limited to a single theory to explain themechanism by which these proteins are altered in the presence ofcarcinoma of the breast, it is proposed that since the histo-physiologyis very similar between the ductal tissues of the breast and those ofthe salivary glands, there may be extra-cellular communication betweenthe two distant tissues (38, 39). This phenomenon has also been observedin nipple aspirates (40, 41) which have yielded many of the same proteinconstituents as observed in Table 4.

The salivary proteome that is altered in the presence of carcinoma ofthe breast was examined in the present studies, and a group of proteinswere identified that have potential diagnostic utility for breastcancer. Saliva as a diagnostic media has potential clinical advantagesbecause it contains numerous proteins and protein fragments that mayhave analytical value. Salivary fluid is continually produced andexcreted in an open-ended circuit, thereby offering a way to obtain“real-time” results. In contrast, blood exists in a “closed-loop”system. Therefore blood, as a circulating media, may contain proteinsthat are a day, a week, or a month old as well as proteins which havepassed numerous times through many organ systems or have been excreted(42). In some cases, saliva and nipple aspirates may be a more usefuldiagnostic fluid than blood.

Use of Salivary Biomarkers to Differentiate Non-cancerous Tissue, BenignTumor, and DCIS in a Test Sample.

In some embodiments, one or more salivary biomarkers are used todifferentiate non-cancerous breast tissue, benign breast tumor andductal carcinoma in situ of the breast by analyzing the salivaryproteome of an individual suspected of having breast cancer, asdescribed above. One or more of the protein biomarkers identified inTables 3 and 4 are identified and quantified in the test patient'ssaliva specimen, and the resulting values are then compared to abiomarker reference panel, which is developed in accordance with theabove-described procedure. The biomarker reference panel is made up of agroup of the same saliva protein constituents developed using DCIS,benign tumor and healthy, non-cancerous (i.e., tumor free) control grouppopulations. Each constituent has associated with it a range ofconcentration values, a mean concentration, and statistical error range.Receiver Operating Characteristic Curves (ROC) curves (sensitivity vs.1-specificity) are constructed for salivary protein concentrations. Theoptimum cutoff value for each marker is determined by using the cutoffvalue that produces the largest percentage of area under its ROC curve.The salivary ROC curves for each marker are compared using a modifiedWilcoxon rank sum procedure. Once determinations have been made for thesensitivity and specificity of each marker, positive and negativepredictive values, and likelihood ratios are calculated. The same typesof analyses are also made for the benign tumor group versus the cancergroup. From comparison of the individual marker values to the referencepanel values, a differential diagnosis of the patient is determined.

For individual protein biomarker values that fall within the range ofcontrol values, a diagnosis of lower risk or likelihood of occurrence ofbreast tumor is determined. A comparison chart similar to that shown inFIG. 3 or 4 may be employed, for example, in which the reference valuesof the biomarkers in breast tumor saliva samples are presented relativeto controls (e.g., mean values for saliva samples from breast tumor-freeindividuals). Alternatively, the reference values may be storedelectronically on a computer readable storage device, and a computeraided comparison is performed and a diagnostic report is prepared, uponinput of the test sample biomarker levels. When the concentration valueof a selected protein biomarker falls within the range for that proteinin the DCIS and/or benign groups of the reference panel, a diagnosis ofelevated risk or likelihood of the presence or occurrence of a breasttumor is appropriate. When the concentration of a protein issignificantly different than the mean concentration of the same proteinin the control group of the reference panel, a diagnosis of high risk orhigh likelihood of the presence of a breast tumor, or of the occurrenceof a breast tumor, is appropriate.

In one embodiment of a screening procedure, the biomarker Q9UBC9/SPRR3(encoded by GenBank Accession No. Q9UBC9 Gene ID. SPRR3), indicated inTables 3 and 4, is quantitated in the saliva of an individual todiagnose a breast cancer, using the above-described saliva samplepreparation and analysis procedures, or equivalent methods. The detectedlevel or value of the biomarker is then compared to reference values ofthe biomarker in the saliva of individuals with breast tumors (eitherbenign fibroadenomas or DCIS). By comparison of the individual's markervalue to the reference value (or range of values), a differentialdiagnosis of the patient is determined, to differentiate between breastcancer and breast cancer-free condition.

In a modification of this procedure, the individual's salivary level ofthe Q9UBC9/SPRR3 biomarker is additionally compared to respectivereference values in the saliva of individuals with DCIS and ofindividuals with benign breast tumor (i.e., fibroadenoma). By furthercomparison of the individual's marker value to the respective referencevalues of the marker in individuals with DCIS or benign breast tumor, afurther diagnosis of the patient is obtained, to differentiate betweenbenign breast tumor and DCIS.

In another embodiment the biomarker Q8N4F0/BPIL1 (encoded by GenBankAccession No. Q8N4F0 Gene ID. BPIL1), indicated in Table 3, isquantitated in the saliva of an individual to diagnose DCIS breasttumor, using the above-described saliva sample preparation and analysisprocedures, or equivalent methods. The detected level of the biomarkeris then compared to respective reference values of the biomarker in thesaliva of individuals with DCIS and of individuals with benign breasttumor (i.e., fibroadenoma). By comparison of the individual's markervalue to the reference values, a differential diagnosis of the patientis determined, to differentiate between tumor-free breast tissue and abreast cancer, or to indicate lower risk or likelihood of the presenceor occurrence, if the value of the test sample falls within the controlvalues for this protein biomarker.

In another embodiment the biomarker P07737/PROF1 (encoded by GenBankAccession No. P07737 Gene ID. PROF1), indicated in Table 3, isquantitated in the saliva of an individual to diagnose benign or DCISbreast tumor, using the above-described saliva sample preparation andanalysis procedures, or equivalent methods. The detected level of thebiomarker is then compared to respective reference values of thebiomarker in the saliva of individuals with DCIS and of individuals withbenign breast tumor (i.e., fibroadenoma). By comparison of theindividual's marker value to the reference values, a differentialdiagnosis of the patient is determined, to differentiate betweentumor-free breast tissue and a breast tumor (either benign or DCIS). Asnoted above, if the value of the test sample falls within the controlvalues for this protein biomarker, a diagnosis of lower risk orlikelihood of the presence or occurrence of either fibroadenoma or DCISis made.

Another embodiment uses the biomarker P01024/C03 (encoded by GenBankAccession No. P01024 Gene ID. C03). No. P01024 Gene ID C03 is importantdue to its central role in the activation of the classical complementsystem and contributes to innate immunity. Its activation is requiredand generally results in an early inflammatory response. As DCIS is avery early stage carcinoma and localized inflammation may be initiallypresent, this protein will present itself as a marker for earlydetection. This biomarker is quantitated in the saliva of an individualusing the above-described saliva sample preparation and analysisprocedures, or equivalent methods. The detected level of the biomarkeris then compared to reference value of the biomarker in the saliva ofindividuals with DCIS. By comparison of the individual's marker value tothe reference value, a diagnosis of the patient is determined, todifferentiate between tumor-free breast tissue and DCIS. As noted above,if the value of the test sample falls within the control values for thisprotein biomarker, a diagnosis of lower risk or likelihood of thepresence or occurrence of DCIS is made. This biomarker is not typicallyassociated with benign tumors. Therefore, in some screeningapplications, the comparative values of the P01024/C03 biomarker in anindividual's saliva will be especially informative as to the likelihoodof the risk or present existence of DCIS in that individual.

In variations of the foregoing embodiments, quantitation and analysis oftwo or more of the above-identified biomarkers are combined to increasethe robustness of the diagnostic test. For example, a screeningprocedure may analyze the comparative levels of Q9UBC9/SPRR3 and one ormore biomarkers that are essentially unique to fibroadenomas (e.g.,ENOA, IGHA2, IL-1ra, S10A7, SPLC2). In some cases, a screening proceduremay analyze the comparative levels of Q8N4F0/BPIL1 and one or morebiomarkers that are essentially unique to DCIS (e.g., CAH6, K2C4, CYTA,FABP4, IGHGI, TRFL, BPIL1, CYTC, HPT, PROF1 and ZA2G), in anindividual's saliva sample. In some cases, a screening procedure mayanalyze the comparative levels of P07737/PROF1 or P01024/C03 in anindividual's saliva relative to the respective biomarker value incontrol saliva samples, to determine a diagnosis of the patient thatdifferentiates between tumor-free breast tissue and breast tumor.

It is believed that the protein biomarkers Q9UBC9/SPRR3, Q8N4F0/BPIL1,P07737/PROF1 and P01024/C03 have not been previously associated withbreast tumors. They are believed to primarily function, respectively, asan indicator of tissue damage, as a transport protein, i.e. associatedwith movement of proteins across a cellular membrane, as acytoskeleton-associated protein, and as an initiator of immuneresponses. The combined screening for saliva levels ofvariously-functioning protein biomarkers such as these potentiallyoffers a more robust diagnostic method than a method that screens forprotein biomarkers associated with only a single physiological function.Additionally, using multiple biomarkers enhances cancer detection byreducing the number of false positives and negatives. This is achievedby using proteins that are associated uniquely with specific biologicalpathways, markers that are tumor specific (benign vs. malignant), and bydetermining if the proteins are up- or down-regulated in the presence ofdisease. Collectively, this information will reduce subjectivity andprovide the clinician with information for superior clinicaldecision-making.

Accordingly, in another embodiment of a diagnostic screening procedure,one or more of the biomarkers Q9UBC9/SPRR3, Q8N4F0/BPIL1, P07737/PROF1and P01024/C03 are quantitated and analyzed along with anotherbiomarker, such as a biomarker that is known to be significantlyup-regulated or down-regulated in benign breast tumors and/or DCIS(e.g., significant at the p<0.001 to p<0.0001 level). Such otherbiomarkers include, for example, those that are known to be associatedwith cell adhesion and/or communication; are associated with thecytoskeleton; are involved with energy metabolism; are associated withimmune response; are inhibitors of cysteine proteases; are indicators oftissue damage; inhibit G1 CDKs, or modulate NK activity; are calciumbinding proteins; are membrane associated proteins; are proteins withbinding functions; are involved with protein degradation and inhibition;are associated with cell signaling; are surface antigens related togrowth; or are involved with transport in cells of the body. Somespecific examples of such biomarkers are identified in Tables 3 and 4.

A patient may be monitored for recurrence or progression of breastcancer after surgery, by testing the status of saliva biomarkers beforeand after surgery, and periodically thereafter. Such differentialidentifications may be used alone or in conjunction with one or moreother diagnostic methods for diagnosing or monitoring a patient forbreast cancer. For instance, the patient may have received therapeutictreatment for breast cancer, with or without prior surgical removal ofcancerous tissue. Analyzing saliva samples for protein biomarkers, inaccordance with the methods described herein, will potentially aid inmaking treatment decisions for the patient. The effectiveness of a givendrug, or radiation therapy, or surgical procedure may be monitored byperiodically determining the status of the saliva biomarkers in thepatient, and comparing them to the same reference panel and/or to thepatient's previous saliva tests.

The potential diagnostic benefits include the overall management ofbreast cancer in women. The diagnosis of breast cancer at an earlierstage allows a woman more choice in selection of various treatmentoptions. A saliva based test is potentially useful in the postoperativemanagement of cancer patients. For example, in some cases, followingtumor removal, a decrease in marker concentration will follow andeventually plateau to within a normal level indicating that the patientis free of disease. In contrast, a persistently high level of salivaryprotein biomarkers will be indicative of tumor recurrence orpersistence. Saliva is potentially a cost effective method formonitoring the effectiveness of chemotherapy in which decreases inmarker concentrations are observed if the treatment regimen iseffective.

TABLE 1 Comparison Up Regulated Down Regulated Total Markers Benign vs.Healthy 14 9 23 Cancer vs. Healthy 20 12 32 Cancer vs. Benign 17 11 28Totals 51 32 83

TABLE 2 Benign vs. Healthy Accession Protein Name Ratio p Value Gene ID.Up-Regulated Proteins in Benign P06733 Alpha enolase 1.4204 0.0006 ENOAP04083 Annexin A1 1.6282 0.0047 ANXA1 P05109 Calgranulin A 1.9393 0.0001S10A8 P06702 Calgranulin B 1.6297 0.0002 S10A9 Q9UBC9 Cornifin beta2.1353 0.0000 SPRR3 P01036 Cystatin S precursor 1.2584 0.0027 CYTSP01877 Ig alpha-2 chain C region 1.2781 0.0213 IGHA2 P01871 Ig mu chainC region 1.256 0.0196 MUC P13646 Keratin, type I cytoskeletal 13 1.31840.0180 K1CM Q9QWL7 Keratin, type I cytoskeletal 17 2.6008 0.0018 K1CQP04264 Keratin, type II cytoskeletal 1 1.4504 0.0002 K2C1 P48666Keratin, type II cytoskeletal 6C 2.0979 0.0003 K2C6C Q9HC84 Mucin 5Bprecursor 1.4306 0.0001 MUC5B P05164 Myeloperoxidase precursor 1.89490.0015 PERM Down-Regulated Proteins in Benign P28325 Cystatin Dprecursor 0.817 0.0455 CYTD P18510 Interleukin-1 receptor antagonistprotein precursor 0.7484 0.0312 IL1RA P22079 Lactoperoxidase precursor0.7408 0.0137 PERL P80188 Neutrophil gelatinase-associated lipocalinprecursor 0.7971 0.0289 NGAL P31151 S100 calcium-binding protein A70.4737 0.0054 S10A7 P04745 Salivary alpha-amylase precursor 0.82450.0023 AMYS P02787 Serotransferrin precursor 0.6968 0.0000 TRFE P02768Serum albumin precursor 0.6922 0.0000 ALBU Q96DR5 Short palate, lung andnasal epith. Ca assoc. protein 2 0.7798 0.0170 SPLC2

TABLE 3 Cancer vs. Healthy Accession Blood Tissue Number Protein NameRatio P Value Gene ID Reported Function (Ref.) (Ref.) Up-RegulatedProteins in Cancer Saliva Q9DCT1 Aldo-keto reductase 1.44 0.0264 AK1E1Detox & reduction — 25 P04083 Annexin A1 3.06 0.0001 ANXA1 Membraneassociated protein 30 25 P05109 Calgranulin A 2.18 0.0001 S10A8 Celladhesion & communication 30 — P06702 Calgranulin B 1.87 0.0001 S10A9Cell adhesion & communication 30 — P23280 Carbonic anhydrase VI 1.520.0003 CAH6 Energy/metabolism 30 27 Q9UBC9 Cornifin beta 1.82 0.0001SPRR3 Indicator of tissue damage — — P13646 Cytokeratin 13 6.56 0.0001K1CM Intracytoplasmatic cytoskeleton protein 30 — P19013 Cytokeratin 46.50 0.0019 K2C4 Intracytoplasmatic cytoskeleton protein 30 25 P48666Cytokeratin 6C 4.41 0.0001 K2C6C Intracytoplasmatic cytoskeletionprotein — — P01040 Cystatin A 2.00 0.0014 CYTA Protein degradation &inhibitor 30 25 P01036 Cystatin SA-III 1.20 0.0115 CYTS Proteindegradation & inhibitor — — Q01469 Epid. Fatty acid-binding prot. 2.10.0362 FABP4 Protein with binding functions 30 — P01857 Ig gamma-1 chainC region 1.44 0.0034 IGHG1 Immunoresponse — — P01871 Ig mu chain Cregion 1.51 0.0011 MUC Immunoresponse — — P06870 Kallikrein 1 precursor1.23 0.0425 KLK1 Serine protease P02788 Lactoferrin 1.58 0.0001 TRFLInhibits G1 CDK's, mod. NK activity 30 26 Q9HC84 Mucin 5B 1.68 0.0001MUC5B Cell adhesion & communication — 36 P05164 Myeloperoxidaseprecursor 2.72 0.0005 PERM Defense Immunoresponse 30 — P31151 S100calcium-binding protein 2.05 0.0001 S100P Calcium binding protein 30 25P31025 Von Ebner's gland protein (lipocalin) 1.26 0.0043 VEGPInflammation — 25 Down-Regulated Proteins in Cancer Saliva Q8N4F0 Bact.Perm.-increasing prot.- 1 0.80 0.0004 BPIL1 Transport 30 — P04264Cytokeratin 1 0.61 0.0001 K2C1 Intracytoplasmatic cytoskeleton protein —25 P01034 Cystatin C 0.72 0.0187 CYTC Inhibitor of cysteine proteases —31 P28325 Cystatin D precursor 0.68 0.001 CYTD Protein degradation &inhibitor — — P00738 Haptoglobin 0.83 0.0023 HPT Indicator of tissuedamage and necrosis 30, 34 — P22079 Lactoperoxidase 0.82 0.0388 PERLTransport — 33 P01833 Poly-IG receptor protein 0.86 0.0234 PIGRImmunoresponse P07737 Profilin-1 0.68 0.0135 PROF1 Cytoskeletonassociated — 25 P02768 Serum albumin precursor 0.73 0.0001 ALBUTransport 30 27 Q96DR5 Short palate, lung and nasal epith. carc. 0.610.0001 SPLC2 Immune response & detox. — 32 assoc. protein 2 P02787Transferrin 0.72 0.0001 TRFE Surface antigen assoc. with growth 34 —P25311 Zinc-alpha-2-glycoprotein 0.84 0.0009 ZA2G Signaling — 29

TABLE 4 Cancer vs. Benign Accession Protein Name Ratio p Value Gene ID.Up-Regulated Proteins in Cancer Q9HC84 Mucin 5B precursor 1.16 0.0046MUC5B P80188 lipocalin precursor 1.18 0.0443 NGAL P01871 Ig mu chain Cregion 1.19 0.0231 MUC P04745 Salivary alpha-amylase precursor 1.190.001 AMYS P23280 Carbonic anhydrase VI precursor 1.29 0.0293 CAH6P02788 Lactotransferrin precursor 1.30 0.0113 TRFL P05164Myeloperoxidase precursor 1.41 0.0487 PERM P01857 Ig gamma-1 chain Cregion 1.43 0.0004 IGHG1 Q9DCT1 Aldo-keto reductase 1.47 0.018 AK1E1P31025 Von Ebner's gland protein 1.55 0.0005 VEGP P04083 Annexin A1 1.860 ANXA1 P10599 Thioredoxin 1.93 0.03 THIO P01040 Cystatin A 1.95 0.0056CYTA P48666 Keratin, type II cytoskeletal 6C 2.07 0 K2C6C P31151 S100calcium-binding protein A7 4.08 0.0005 S10A7 P13646 Keratin, type Icytoskeletal 13 4.76 0 K1CM P19013 Keratin, type II cytoskeletal 4 5.590.0013 K2C4 Down-Regulated Proteins in Cancer P04264 Keratin, type IIcytoskeletal 1 0.42 0 K2C1 Q9QWL7 Keratin, type I cytoskeletal 17 0.580.001 K1CQ P01034 Cystatin C precursor 0.67 0.0246 CYTC P13796 L-plastin0.69 0.0145 PLSL P06733 Alpha enolase 0.73 0.0106 ENOA P01833Polymeric-Ig receptor 0.76 0.0002 PIGR P12273 Prolactin-inducibleprotein precursor 0.77 0.0012 PIP Q96DR5 Short palate, lung and nasalepithelium 0.78 0.0219 SPLC2 carcinoma associated protein 2 precursorP07477 Trypsin I precursor 0.82 0.0196 TRY1 P28325 Cystatin D precursor0.83 0.0155 CYTD Q9UBC9 Small proline-rich protein 3 0.84 0.0228 SPRR3

TABLE 5 Low risk Subjects vs. Stage 0 Cancer Subjects Level 3 - Changesgreater than 2-fold from good quality signals that pass a visualinspection Swiss Predicted SSP Acc. No. Type Lane Protein Name LevelProt ID Locus MW MW Signal Change FoldChange 5602 A13920 CONTROL 25Annexin I 3 P46193 301 38 40 0 − 26.65  2501 A14020 CONTROL 5 Annexin II3 P07355 302 36 39 1 − div/0 6903 A92820 CONTROL 27 Apaf-1 3 O14727 317130 137 1 − div/0 5702 R10820 CONTROL 22 BAG-1-58KD 3 Q99933 57350/46/33 58 1 − 12.90  6601 C41720 CONTROL 27 Calreticulin-51KD 3 P1421112317 60 51 1 − div/0 6702 C41720 CONTROL 27 Calreticulin-54KD 3 P1421112317 60 54 1 − div/0 9703 C20820 CANCER 30 E-Cadherin 3 P12830 999 120120 1 − div/0 5901 N38620 CONTROL 23 eNOS/NOS Type III 3 P29474 4846 140140 1 − div/0 3901 C26220 CONTROL 9 g-Catenin 3 Q15151 3728 82 82 1 −div/0 6401 G16720 CONTROL 28 GRB2 3 P29354 81504 24 24 0 + 3.09 8401G16720 CONTROL 33 GRB2-24KD 3 P29354 81504 24 24 1 + 3.86 8501 G16720CONTROL 33 GRB2-28KD 3 P29354 81504 24 28 0 + 10.15  1601 M93620 CANCER5 Mint3/X11g-61KD 3 O88888 9546 61 61 0 + 4.65 4904 M94120 CONTROL 14MSH3-138KD 3 P20585 4437 127 138 1 − div/0 3607 P35220 CONTROL 7 PP1 3P08129 5499 36 41 1 − 2.18 202 R23520 CANCER 2 Ral A 3 P11233 5898 24 261 − 21.01  2101 S10520 CANCER 8 Spot 14 3 Q92746 7069 17 17 0 + 2.002601 T57120 CONTROL 2 Tau-53KD 3 P10636 4137 50-68 53 1 + 3.02

TABLE 6 Low risk Subjects vs. Stage 0 Cancer Subjects Level 2 - Changesgreater than 2-fold from good quality signals that do not pass a visualinspection Swiss Predicted SSP Acc. No. Type Lane Protein Name LevelProt ID Locus MW MW Signal Change FoldChange 7503 CANCER 20alpha-Tubulin 2 0 0 55 58 1 − 1.92 5504 F14220 CONTROL 23 basic FGF-25KD2 P09038 2246 18-24 25 1 + 3.30 6602 C80420 CONTROL 29 CD38 2 P28907 95246 41 1 − div/0 4601 C45820 CONTROL 17 CDC25B-53KD 2 O43550 994 63 530 + 2.20 7702 F19720 CONTROL 30 fyn 2 P06241 2534 59 55 0 + 3.51 4501G59720 CONTROL 14 GST-p 2 P09211 2950 23 25 1 + 3.89 7404 H10520 CANCER20 KNP-1/HES1 2 0 0 28 28 1 − 4.38 7601 L15620 CONTROL 31 lck-53KD 2P06239 3932 56 53 1 + 3.67 2301 N13320 CANCER 8 NES1 2 O43240 5655 30 280 − 2.00 4201 N42420 CONTROL 20 NTF2 2 0 0 15 15 0 + 1.89 3402 P11920CONTROL 9 p24 2 P97799 22360 24 24 1 + 4.48 5608 A36520 CONTROL 26Phospho-Akt (S473) 2 P31749 207 59 54 0 + 3.89 3610 P67920 CONTROL 7PKBa/Akt-53KD 2 P31749 207 59 53 1 + 2.56 7608 P97220 CANCER 21 PKR 2Q03963 54287 58 62 1 − 31.10  9201 CANCER 35 Rap2 2 0 0 21 21 1 − div/06501 R73920 CONTROL 29 Rho-25KD 2 P03749 387 21 25 1 + 3.06 6607 R41220CANCER 14 RIP 2 Q13546 8737 74 66 1 − 2.16

TABLE 7 Low risk Subjects vs. Stage 0 Cancer Subjects Level 1 - Changesgreater than 2-fold from low quality signals Swiss Predicted SSP Acc.No. Type Lane Protein Name Level Prot ID Locus MW MW Signal ChangeFoldChange 7406 556596 CANCER 24 14-3-3 1 Q9S928 55948 30 30 2 + 3.222603 A27320 CANCER 11 Acetylcholinesterase 1 P22303 43 68 60 2 + 104.25 8503 A40720 CONTROL 33 ApoE 1 P02649 348 36 36 2 − div/0 9503 A37720CANCER 35 Arp3 1 0 0 50 51 2 − 5.64 9601 A37720 CONTROL 37 Arp3 1 0 0 5050 2 − 2.70 901 G73320 CONTROL 1 BiP/GRP78 1 P11021 3309 78 74 2 + 2.249508 C41720 CANCER 35 Calreticulin 1 0 0 60 60 2 + 2.26 7504 C14520CANCER 22 Csk 1 P32577 64019 50 56 2 − 50.52  1701 C37020 CANCER 4E-Cadherin 1 P12830 999 120 120 2 − div/0 2602 H62120 CANCER 10 MLP/XIAP1 P98170 331 57 60 2 + 1.99 1404 H22020 CANCER 5 Hsp40 1 P25685 3301 4043 2 + 2.09 1501 M93620 CANCER 5 Mint3/X11g-55KD 1 O88888 9546 61 55 2 +3.22 (doublet) 4303 N25720 CONTROL 15 Nm23 1 P15531 4831 17 19 2 + 2.729702 N41520 CANCER 28 nNOS/NOS type I-172KD 1 P29476 4842 155 172 2 +6.07 9704 P49620 CANCER 31 Paxillin-147KD 1 P49024 5829 68 147 2 + 2.519606 P49620 CANCER 31 Paxillin-75KD 1 P49024 5829 68 75 2 − 3.67 8502P56720 CONTROL 34 PCNA 1 P12004 5111 36 28 2 + 2.24 8901 P71720 CONTROL34 PDI 1 P05307 64714 55 55 2 + 2.00 4602 P62220 CANCER 12 PKR/p68Kinase 1 P19525 5610 68 60 2 + 3.47 2401 R56220 CONTROL 2 Rac1 1 P15154207 21 24 2 + 2.86 9302 CONTROL 37 Rap2 1 0 0 21 20 2 − div/0 2702G12920 CANCER 9 Ras-GAP 1 P20936 5921 120 128 2 − div/0 7902 R68320CONTROL 32 Rb 1 P13405 19645 110 104 2 + 3.82 2901 G16920 CONTROL 5Stat1 (N-terminus) 1 P42224 6772 91/84 86 2 − div/0 603 T93820 CANCER 2TLS 1 P35637 2521 65 61 2 − 4.19

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While the preferred embodiments of the invention have been shown anddescribed, modifications thereof can be made by one skilled in the artwithout departing from the spirit and teachings of the invention. Theembodiments described herein are exemplary only, and are not intended tobe limiting. Many variations and modifications of the inventiondisclosed herein are possible and are within the scope of the invention.Accordingly, the scope of protection is not limited by therepresentative description set out above, but is only limited by theclaims which follow, that scope including all equivalents of the subjectmatter of the claims. The disclosures of all patents, patentapplications, and publications cited herein are hereby incorporatedherein by reference, to the extent that they provide exemplary,procedural, or other details supplementary to those set forth herein.

1. A method of diagnosing the likelihood of the presence or occurrenceof breast tumor in a test subject, the method comprising: (a) measuringin a saliva sample from the test subject the concentration of at least afirst protein biomarker, wherein each said biomarker is known to bedifferentially expressed in breast tumor and tumor-free breast tissue,wherein said breast tumor comprises benign fibroadenoma or ductalcarcinoma in situ of the breast (DCIS), to provide a set of test datacomprising a concentration value of each said protein biomarker in saidsaliva sample; (b) comparing said test values to a reference panelcomprising (1) a mean concentration value of each said protein in salivafrom a group of breast tumor-free individuals (reference control group),(2) a mean concentration value of each said protein in saliva from agroup of individuals with DCIS (reference DCIS group), or from a groupof individuals with benign fibroadenoma of the breast (reference benigngroup), or from both the DCIS group and the benign group; (c)determining from said comparison a diagnosis of likelihood of thepresence or occurrence of a breast tumor in the test subject.
 2. Themethod of claim 1, wherein in (a), at least said first biomarker isknown to be differentially expressed among benign fibroadenoma, DCIS andtumor-free breast tissue; in (b), (2) comprises: (2′) a meanconcentration value of each said protein in saliva from said referenceDCIS group, and (2″) a mean concentration value of each said protein insaliva from said reference benign group, and in (c), said determiningcomprises determining from said comparison a diagnosis of likelihood ofthe presence or occurrence of either DCIS or fibroadenoma of the breastin the test subject.
 3. The method of claim 2, wherein the concentrationvalue of at least said first protein biomarker in said reference panelis significantly different in the saliva of said reference DCIS groupand/or in the saliva of said reference benign group, relative to therespective level of each said protein biomarker in the saliva of saidreference control group.
 4. The method of claim 3, wherein theconcentration value difference of at least said first protein biomarkeris significant at a level in the range of p<0.05 to p<0.0001.
 5. Themethod of claim 3, wherein at least said first protein biomarker isselected from the group consisting of CAH6, K2C4, CYTA, FABP4, IGHGI,TRFL, BPIL1, CYTC, HPT, PROF1 and ZA2G, and, in (c), said determiningcomprises determining from said comparison a diagnosis of likelihood ofthe presence or occurrence of DCIS in the test subject.
 6. The method ofclaim 3, wherein at least said first protein biomarker is selected fromthe group consisting of ENOA, IGHA2, IL-1ra, S10A7, SPLC2, and, in (c),said determining comprises determining from said comparison a diagnosisof likelihood of the presence or occurrence of fibroadenoma in the testsubject.
 7. The method of claim 1, wherein said reference panel isprepared by analyzing salivary proteins by isotopic labeling and liquidchromatography tandem mass spectrometry to characterize salivaryproteins from each said group, and determining from said analysis thedifferential concentrations of said protein biomarkers in individualswith ductal carcinoma in situ of the breast, in individuals with benignfibroadenoma of the breast, and in individuals free of both ductalcarcinoma in situ and benign fibroadenoma.
 8. The method of claim 1,wherein, in (a), said measuring comprises analyzing said samplecomprising salivary proteins by isotopic labeling and liquidchromatography tandem mass spectrometry to characterize said proteins.9. The method of claim 8, wherein said isotopic labeling comprisesdifferential isotopic labeling of salivary proteins of at least firstand second saliva samples.
 10. The method of claim 1, wherein, in (b),said comparing yields a comparison result in which the concentrationvalue of at least said first protein biomarker is a significant changerelative to the mean concentration value of the respective protein inthe control group of the reference panel.
 11. The method of claim 2,wherein said saliva sample is a first saliva sample from said testsubject, and, in (a), the set of test data is a first set of test data,and the method further comprises: (d) obtaining a second saliva samplefrom said subject subsequent to said first sample; (e) measuring theconcentration of at least said first protein biomarker in the secondsaliva sample, to provide a second set of test data comprising a secondconcentration value of each said protein biomarker in said salivasample; (f) comparing the second set of test data to said referencepanel; (g) determining from the result of said comparing a diagnosis oflikelihood of the presence or occurrence of either DCIS or benignfibroadenoma of the breast in the test subject.
 12. The method of claim11, further comprising (h) comparing said second set of test data tosaid first set of test data to determine whether a difference in theconcentration value of at least said first protein biomarker existsbetween said first and second sets of test data for said test subject.13. The method of claim 12, wherein said first saliva sample is obtainedprior to surgical removal of cancerous breast tissue from said subject.14. The method of claim 13, wherein said test subject has receivedtherapeutic treatment for breast cancer prior to obtaining said secondsaliva sample.
 15. The method of claim 14 wherein, in (g), determining acomparative decrease in at least said first protein biomarkerconcentration in said second sample relative to said first sampleindicates that the therapeutic treatment is effective.